Operators of mobile systems, such as Universal Mobile Telecommunications Systems (UMTS) and its offspring including LTE (Long Term Evolution) and LTE-Advanced, are increasingly relying on wireless small cell radio access networks (RANs) in order to deploy indoor voice and data services to enterprises and other customers. Such small cell RANs typically utilize multiple-access technologies capable of supporting communications with multiple users using radio frequency (RF) signals and sharing available system resources such as bandwidth and transmit power. While such small cell RANs operate satisfactorily in many applications, there exists a need for further improvements in small cell RAN technologies.
One such improvement includes use of the citizens band radio spectrum. The citizens broadband radio spectrum is a band now used primarily by Navy radars in coastal areas as well as PtP WiMax links at 25,000 locations. As diagrammed in FIG. 1, the FCC is opening 15 10 MHz unpaired channels for CBS devices, a device being termed a CBSD, the same referring to a citizens broadband radio service, which is essentially a fixed location base station. A new Spectrum Access System (SAS) will control access to the band for CBSDs, and the SAS will likely be implemented by a few large players, e.g., Google, under the FCC's oversight.
The new SAS will control access to the band according to various priorities and devices need to be authorized by the SAS for radiating in the allocated spectrum. Having first priority are the incumbent users, e.g., the Navy, PtP links, and so on. The second priority will be CBSDs operating with priority access licenses (these are generally three-year licenses per census tract, but are renewable).
The third priority will be CBSDs operating according to a Generic Authorized Access (GAA) model, which is based on a license-by-rule framework.
In more detail, and referring to FIG. 2, the overall 150 MHz spectrum is currently divided into a lower 100 MHz section and an upper 50 MHz section, with the lower 100 MHz being used by Navy radars in coastal areas and space-to-earth FSS stations. The upper 50 MHz is currently used by fixed wireless BB service, three ground radar stations, 86 grandfathered FSS space-to-earth stations, and Navy radar for ships located further than 44 miles from the coast.
In the new system, the 150 MHz band will be channeled into the noted 15 unpaired 10 MHz blocks (see FIG. 3):
The lower 100 MHz will operate according to the noted three tier model, and the upper 50 MHz will operate according to a two-tier model.
Lower 100 MHz:
Tier 1: Incumbents (Navy radars and FSS Space-to-Earth stations)
Tier 2: CBRS Priority Access Licensees (PAL)
Tier 3: CBRS Generic Authorized Access (GAA)
Upper 50 MHz:
Tier 1: Incumbents (mainly PtP Fixed WiMax links @ 25,000 known locations)
Tier 2: CBRS GAA (after a transition period (˜5 yrs), one model will apply, and incumbents will re-classified as GAA)
The SAS will detect activity by incumbents, e.g., Navy radars, and will operate so as to push down to the CBSD information about such activity so as to allow dynamic allocation in a way to vacate channels needed for incumbent use. That is, the SAS is responsible for installing sensors so as to allow an environment sensing capability (ESC). An implementation of the SAS would be by one or more servers operating, e.g., as a cloud service, with an appropriate domain.
The priority access licenses (PAL) will operate as follows. Such are only available for the lower 100 MHz band (see figure above), and will be allocated per census tract. It is noted in this regard that approximately 74,000 census tracts are in the US, and the design targets an optimal population of 4000 for each tract. There will be a maximum of seven PAL licenses given for any census tract (only seven, such that the SAS can dynamically adjust channel usage if needed, e.g., if an incumbent is detected). One licensee can have at most 4 PAL licenses or channels in any given census tract.
PAL licensing will be by a competitive bidding process every three years, with an automatic expiration after that time. For the very first licensing period, a PAL license may be acquired for 3+3 years. All PAL licenses will expire at the same time, so all PAL's will be re-auctioned every three years.
PAL licenses to a tract will be awarded only if there are more bidders than available PAL channels. Otherwise, no PAL licenses will be awarded, and all channels will be available as GAA.
GAA may potentially apply for the whole 150 MHz band, i.e., up to 15 channels. A “license by rule” framework will be applied, where the premises owner has de facto control of on-site deployments. As stated by the FCC, there may be limited opportunities for citizens broadband radio service users to deploy and utilize CBSDs in indoor areas without the permission of facility owners. In addition, an SAS can authorize GAA devices into PAL channels that are not used.
This Background is provided to introduce a brief context for the Summary and Detailed Description that follow. This Background is not intended to be an aid in determining the scope of the claimed subject matter nor be viewed as limiting the claimed subject matter to implementations that solve any or all of the disadvantages or problems presented above.